Low-Temperature Prepared Multi-Elements Doped CeO₂ Electrolyte

CeO₂ materials doped with the di- or tri-valent metals possess high oxide ionic conductivity at low temperature for potential electrolyte use in intermediate temperature solid oxide fuel cell (SOFC). However, multi-elements doped CeO₂-based electrolyte, (La_1-x-ySr_xBa_y)_0.175Ce_0.825O_2-δ (LSBC) in this work, with pure phase is difficultly synthesized at low calcination temperature. High sintering temperature, e.g. > 1500°C, is also needed in conventional mixed oxide method. In this work, nanoparticles less than 50nm of LSBC can be prepared by solution-evaporation method at constant temperature. Pure fluorite crystal structure can be obtained lower than 700°C. The optimal mole ratio of LSBC/citric acid in prepared solution is 1/2 to achieve homogeneous composition and pure phase of LSBC. Small grain size of about 1μm average is observed for 1300°C-microwave sintered LSBC by solution-evaporation method. The ionic conductivity of 1400°C-conventional sintered and 1300°C-microwave sintered LSBC prepared by solution-evaporation method is about 0.006 S/cm at 600°C but less than 0.004 S/cm at 600°C even for 1500°C-conventional sintered LSBC prepared by mixed oxide method.